Low noise fuel pump with variable pressure regulation
View Patent ↗An engine assembly may include an engine structure defining a combustion chamber, a fuel injector in fluid communication with the combustion chamber, a fuel supply and a fuel pump assembly. The fuel pump assembly may include a housing, a reciprocating member, and a solenoid valve assembly. The housing may define an inlet in fluid communication with the fuel supply, an outlet in fluid communication with the fuel injector, and a bypass passage. The reciprocating member may be located within the housing to define a compression chamber in fluid communication with the inlet, the outlet, and the bypass passage. The solenoid valve assembly may include a valve member located within the bypass passage and displaceable between open and closed positions to selectively provide fluid communication between the compression chamber and the fuel supply during a compression stroke of the reciprocating member.
1. An engine assembly comprising:
an engine structure defining a combustion chamber;
a fuel injector in fluid communication with the combustion chamber;
a fuel supply; and
a fuel pump assembly including a housing, a reciprocating member, and a solenoid valve assembly, the housing defining an inlet in fluid communication with the fuel supply, an outlet in fluid communication with the fuel injector, and a bypass passage, the reciprocating member being located within the housing to define a compression chamber in fluid communication with the inlet, the outlet, and the bypass passage, the solenoid valve assembly including a valve member located within the bypass passage and displaceable between open and closed positions to selectively provide fluid communication between the compression chamber and the fuel supply during a compression stroke of the reciprocating member, the valve member being in the open position during an entirety of a compression stroke of the reciprocating member to provide a controlled leak path between the compression chamber and the fuel supply through the bypass passage.
2. The engine assembly of claim 1 , wherein the fuel pump assembly includes a first inlet valve assembly located between the fuel supply and the compression chamber, the first inlet valve assembly being displaceable between an open position and a closed position, the first inlet valve assembly providing fluid communication between the compression chamber and the fuel supply when in the open position and isolating the compression chamber from fluid communication with the fuel supply when in the closed position.
3. The engine assembly of claim 2 , wherein the first inlet valve assembly is maintained in the closed position during a compression stroke of the reciprocating member.
4. The engine assembly of claim 2 , wherein the first inlet valve assembly includes a mechanical valve displaceable between the open and closed positions based on a pressure within the compression chamber.
5. The engine assembly of claim 4 , wherein the mechanical valve is maintained in the closed position during compression strokes of the reciprocating member due to a fuel pressure within the compression chamber being greater than a fuel pressure in the fuel supply.
6. The engine assembly of claim 2 , wherein the fuel pump assembly includes an outlet valve assembly located between the fuel injector and the compression chamber, the outlet valve assembly being displaceable between an open position and a closed position, the outlet valve assembly providing fluid communication between the compression chamber and the fuel injector when in the open position and isolating the fuel injector from fluid communication with the compression chamber when in the closed position.
7. The engine assembly of claim 6 , wherein the fuel pump assembly includes a relief valve assembly located between the outlet valve assembly and the fuel injector, the relief valve assembly being displaceable between an open position and a closed position, the relief valve assembly providing fluid communication between a pressurized fuel feed to the fuel injector and the fuel supply when in the open position and isolating the pressurized fuel feed from fluid communication with the fuel supply when in the closed position.
8. The engine assembly of claim 1 , wherein the valve member is in the closed position during an entirety of a suction stroke of the reciprocating member.
9. The engine assembly of claim 1 , wherein the fuel supply includes a fuel tank and the fuel pump assembly includes first and second flow paths in fluid communication with the fuel tank, a fuel supply valve being located in the first flow path and preventing fuel flow from the compression chamber to the fuel tank through the first flow path, and a restriction member being located in the second flow path and limiting fuel flow from the compression chamber to the fuel tank through the second flow path.
10. The engine assembly of claim 1 , wherein the valve member is in the closed position during the compression stroke of the reciprocating member during a maximum fuel demand condition, the valve member being in the open position during the entirety of a compression stroke during a reduced fuel demand condition relative to the maximum fuel demand condition.
11. A fuel pump assembly comprising:
a housing defining an inlet in fluid communication with a fuel supply, an outlet in fluid communication with a fuel injector, and a bypass passage in fluid communication with the fuel supply;
a reciprocating member located within the housing to define a compression chamber in fluid communication with the inlet, the outlet, and the bypass passage; and
a solenoid valve assembly including a valve member located within the bypass passage and displaceable between open and closed positions to selectively provide fluid communication between the compression chamber and the fuel supply during a compression stroke of the reciprocating member, the valve member being in the open position during an entirety of a compression stroke of the reciprocating member to provide a controlled leak path between the compression chamber and the fuel supply through the bypass passage.
12. The fuel pump assembly of claim 11 , further comprising a first inlet valve assembly located between the fuel supply and the compression chamber, the first inlet valve assembly being displaceable between an open position and a closed position, the first inlet valve assembly providing fluid communication between the compression chamber and the fuel supply when in the open position and isolating the compression chamber from fluid communication with the fuel supply when in the closed position.
13. The fuel pump assembly of claim 12 , wherein the first inlet valve assembly is maintained in the closed position during a compression stroke of the reciprocating member.
14. The fuel pump assembly of claim 12 , wherein the first inlet valve assembly includes a mechanical valve displaceable between the open and closed positions based on a pressure within the compression chamber.
15. The fuel pump assembly of claim 14 , wherein the mechanical valve is maintained in the closed position during compression strokes of the reciprocating member due to a fuel pressure within the compression chamber being greater than a fuel pressure in the fuel supply.
16. The fuel pump assembly of claim 12 , further comprising an outlet valve assembly located between the fuel injector and the compression chamber, the outlet valve assembly being displaceable between an open position and a closed position, the outlet valve assembly providing fluid communication between the compression chamber and the fuel injector when in the open position and isolating the fuel injector from fluid communication with the compression chamber when in the closed position.
17. The fuel pump assembly of claim 16 , further comprising a relief valve assembly located between the outlet valve assembly and the fuel injector, the relief valve assembly being displaceable between an open position and a closed position, the relief valve assembly providing fluid communication between a pressurized fuel feed to the fuel injector and the fuel supply when in the open position and isolating the pressurized fuel feed from fluid communication with the fuel supply when in the closed position.
18. The fuel pump assembly of claim 11 , wherein the valve member is in the closed position during an entirety of a suction stroke of the reciprocating member.
19. The fuel pump assembly of claim 11 , wherein the fuel supply includes a fuel tank and the fuel pump assembly includes first and second flow paths in fluid communication with the fuel tank, a fuel supply valve being located in the first flow path and preventing fuel flow from the compression chamber to the fuel tank through the first flow path, and a restriction member being located in the second flow path and limiting fuel flow from the compression chamber to the fuel tank through the second flow path.
20. The fuel pump assembly of claim 11 , wherein the valve member is in the closed position during the compression stroke of the reciprocating member during a maximum fuel demand condition, the valve member being in the open position during the entirety of a compression stroke during a reduced fuel demand condition relative to the maximum fuel demand condition.